This invention relates to a carriage with a crucible for tapping molten metal from aluminum electrolyzers and the like, and including a movable tapping tube adapted to be inserted into the metal melt from which tapping shall take place, ejector means for sucking molten metal through the tapping tube, a discharge tube for delivering collected metal from the crucible and possible compressed air means for discharging collected metal through the discharge tube.
A previously commonly used method for bringing the movable tapping tube down into the melt for sucking up the same into the crucible and to couple the tapping tube to the crucible, has involved manual movement of the tapping tube which has constituted a separate unit in relation to the tapping tube and the crucible thereon. It is self-evident that such manual handling of this tapping tube has many disadvantages. One of the most important considerations is the risk or danger because of the high temperatures which occur, not only in the melt to be collected from the electrolyzer, but also in the tapping tube itself and other members in the structures employed, as a consequence of the heat influence from the melt.
Another method which has been proposed for mechanizing the tapping process has been based on suspension of the crucible in a crane, the crucible having in such case been provided with a fixed tapping tube which together with the whole crucible is directed to the desired position for tapping. This method, however, involves disadvantages, in the first place because of the fact that expensive crane equipment is occupied unnecessarily, and in the second place because the exact insertion of the tapping tube through a hole in the crust on the electrolyzer is very difficult by means of those cranes which are usually available.